The present invention relates to an improvement in a lifting apparatus, particularly for lighting fittings and not, for shooting studios.
More particularly, the invention concerns an apparatus of the above kind that allows avoiding, or at least dramatically reducing, effects of possible stresses that could act on the apparatus and that could destabilising the same apparatus.
As it is known, in the cinema and/or television shooting field, and particularly the indoor shootings, many fittings are suspended from the ceiling by lifting apparatuses. Mainly, but not exclusively, they are lighting fittings.
Lifting apparatuses are generally provided with a manually or motor controlled horizontal movement and with a manually or motor controlled vertical movement.
One of the main problems that must be faced up when using this kind of apparatuses is due to the fact that during the motion of the lifting apparatus, supporting a very heavy fitting, the same lifting apparatus must be as more stable as possible.
In fact, every slight motion can, in view of the long arms, induce remarkable stresses on the same apparatus, with the obvious consequences.
Apparatuses presently employed are not able to completely satisfy this kind of needing.
In the most recent apparatuses, it is provided a double pantograph structure, wherein it is necessary to be able that, beside the needing of obtaining a determined stability, it is guaranteed that every displacement caused on an arm of a parallelogram corresponds to an analogous displacement on the arm of the other parallelogram.
To obtain this kind of result, following any kind of movement of the apparatus, i.e. both in extension and retraction of the apparatus, at present a solution is used providing, both above and at the bottom on the double parallelogram structure, a pair of horizontal slots, and a vertical slot, allowing to transfer every movement acts on an arm of a parallelogram, on the corresponding arm of the other parallelogram.
However, this kind of solution does not allow to completely solving the problems connected with the transmission of the motion and with the stabilisation of the structure.
In view of the above, the Applicant has realised a solution able to solve all the above mentioned problems.
Main object of the present invention is that of providing an apparatus allowing to realise an apparatus of the above kind having optimum stability features during its displacement.
It is therefore specific object of the present invention an improved lifting apparatus, particularly for lighting fittings and not, for shooting studios, comprising a pair of pantograph structures, provided side by side, spaced and substantially parallel each other, provided above with coupling suspension means and at the bottom with means for coupling the fitting to be lifted, motorization means, to operate both said parallelogram structures, provided above, between said two parallelogram structures and coupling means to connect said motorization means with each one of said parallelogram structures, said apparatus being characterised in that the upper and lower end arms of each one of said pantograph structures are provided with teeth meshing with corresponding teeth provided on the corresponding arm of the same pantograph structure.
Preferably, according to the invention, said end arms of each pantograph structure are rotatably pivoted on plate means.
Still according to the inventions said teeth of said end arms are section bars.